1. Field of the Invention
The present invention relates to drill bits and more particularly, to counterbore drill bits adapted to enlarge an existing hole.
2. Description of the Prior Art
When installing safety alarms, such as intrusion alarms, it is conventional practice to mount alarm sensors in wooden or metal frames. While many of these alarm systems are prewired at the time of the construction of the building, when expanding or updating a system, it often becomes necessary to enlarge a hole through which an end of an existing wire extends. If the wire is pushed back through the hole, it often drops between studs or framing, thereby creating difficult retrieval problems requiring that the wire be fished from a substantially inaccessible location. Any attempt to enlarge a hole while the wire extends through the hole necessarily results in substantial damage to or cutting of the wire. The drilling of a second hole adjacent the first not only requires that the wire be fished from the first hole, but also leaves the unsightly first hole.